Circuit breaker



July 12, 1927.- 1,635,544

L. N. CRICHTONI CIRCUIT BREAKER Filed Sept; 27, 1922 WITNESSES: INVENTOR Les/kMCr/chfon.

4 ATT NEY Patented July 12, 1927.

UNITED STATES LESLIE N. CBICHTON, F WILKINSBURG,

HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN-- SYLVANIA.

PATENT OFFICE.

PENNSYLVANIA, ASSIGNOR TO WESTING- CIBCUIT BREAKER.

Application filed September 27, 1922. Serial No. 580,767.

My invention relates to circuit breakers and particularly to means for extinguishing arcs that are formed across the relatively movable contact members thereof.

6 The objects of my invention are the pro vision of means for utilizing magnetic forces incident to the flow of current through the circuit breaker for assisting in the rupture of the circuit and of means whereby the ef- 1 fectiveness 0 such forces is substantially proportional. to the strength of the current passing through the interrupter.

Another ob ect of my invention is to provide means for causing the arcing tips to re 16 turn to their normal positions after the magnetic forces incident to the generation of the arc have ceased.

As shown in the accompanying drawing,

Figure 1 is a view, in side elevation, of a ortion of a circuit breaker embodying my invention, and I Fig. 2 is a side elevational view looking from the right of Fig. 1.

Only so much of the circuit breaker is shown as is necessary to a clear description of my invention, the apparatus being intended for employment as an oil-type breaker but the oil or uenching fluid tank within which the move le contact members are to be mounted is not shown.

A lifting rod 3 is employed for raising and lowering a bridging memberv 4 to make and break a circuit across stationary contact members 5 that are secured to conductors 6.

-Arcin tips 7 are pivotally supported by 'the con uctors 6. upon ins 8, the lower ends of the tips 7 bemg rounded and mounted to bear against upper' side of the 40 bridging member 4. Coiled springs 9-10 are disposed around the pins 8 and the conductors 6 and abut againsto posite sides of the arcing tips 7 to yielding y hold them in the position shown in Fig. 2.

As shown in the drawing, the bridging member 4 has been lowered to break the circuit across the stationary contact members 5 and is at the point of separation from the arcing tips 7. Further downward movement of the bridging member will result 1n the formation of arcs between it and the arcing tips. 7.

Electric current. in passing through the conductors 6, arcing tips 7 and bridging member 4, follows a path of substantially U-shape, thereby creating opposing mag netic forces in the zone lying between the conductors 6 and the arcing tips 7 which tend to bias the arcing'tips 7 outwardly about their pivots 8.

If, when the bridgin member 4 has been lowered to a position wiere it no longer engages the arcing tips 7, the current is of suflicient strength, the magnetic forces will move the arcing tips 7, against the tension of the spring portions 9, to the dotted-line positions A carrying with them the arc terminals that have been established upon their lower rounded ends. This movement lengthens the arc streams and causes them to move through the cooling medium within the breaker tank (not shown) and thereby serves to more quickly extinguish the arcs. The magnetic forces, in addition to effecting movement of the arc terminals, also exercise a blowout effect upon. the arc streams.

If the current assing through the circuit at the time of rupture is of such small value that no appreciable magnetic forces: are set up between the conductors 6, the arcs that are formed will be readily broken by the mere separation of the bridging member and the arcing tips. With currents of greater strength, the magnetic forces will, of course, be proportional thereto, and the length of the path of movement of the arcing tips 7 and the length of the arc streams will increase in proportion to the strength of the ma etic forces.

he ortions 10 of the helical spring are put un er compression during the outward movement of the arcing tips 7 as portions 9 of the s ring are held between the bases of the con uctors 6 and the stop members 11. By this arrangement, portions 9 ress upon the arcing tips 7 during the first part of their rotation but, upon spring portions 9 striking the stop ,members 11, further movement of the spring parts 9 being thereby prohibited, the arcing tips 7 are carried through the remaining arcs by the magnetic blowout forces.

Stop members 12 limit the extreme outward position of thearcing tips 7. After the arcing tips have reached their extreme positions, a shown in the dotted-line position A of Fig. 1, and the magnetic blowout made without departing of the spring portions cause the arcing tips to turn into a normal position, shown in full lines. As the bridging member 4 is drawn upward in the operation of closing contact, arcing tips 7 are encountered and are carried upward to the dot-and-dash position B against the tension of spring portion 9 where they remain so long as the contacts are closed.

While my invention is intended primarily for circuit breakers of the oil ty e it may also be utilized in connection wit breakers of the carbon or air-break type.

Various modifications and changes may be from the s irit'and scope of the invention, as define by the accompanying claims.

I claim as my invention:

1. The combination with a pair of relatively movable main contact members, of an arcing tip pivotally supported adjacent to one of the said members, means for yieldingly holding the arcing tip at a predetermined position when the main contact memhere are separated, the contact members and the arcing tip being disposed for creating repellent magnetic forces to effect movement by the arcing tip beyond the said position during the opening operation of the circuit interrupter.

2. In a circuit interrupter, an arcing tip comprising a. finger member, a shaft at an angle thereto, a spiral sprin mounted on said shaft, means for tensioning and limiting the rotation of said spring, the end portions of said spring being bent to engage the opposite sides of said finger, whereby movement of said finger is controlled during the opening and closing of said circuit interrupter.

3. In a circuit interrupter, a pair of relatively movable contact members, an arcing tip normally disposed in alinement with the contact members when in their open position, and resilient means for biasing the arcing tip to the normal position, the resilient means being stressed during the closing operation of the interrupter whereby the arcing tip tends to snap beyond its normal position upon the opening of the circuit interrupter.

4. In a circuit interrupter, a pair of relatively movable contact members, an arcing tip normally disposed in alinement with the contact members when in their open position, and resilient means for biasing the arcing tip to the normal position, the resilient means bein stressed during the closing op eration of the interrupter whereby the arcing tip tends to snap beyond its normal position upon the opening of the circuit interrupter under the combined influences of the resilient means and magnetic forces.

In testimony whereof, I have hereunto subscribed my name this th day of September, 1922.

LESLIE N. CRICHTON. 

